So true, particularly with live performances. If you go to classical music concerts or other traditional forms of live music, you also realise how much more dynamic and engaging - if not overwhelming, the sound can be when there is no compression, use of faders, filters or other tricks of sanitizing recordings for the mass-market. Add to that the visual aspect of real people with first-rate instruments and you enter a different world of experience.
For comparison, after a great concert last year, I picked up a studio CD that the string quartet's touring company offered for sale, hoping for some of the thrill and energy I remembered but there were only glimpses of it - like many other classical recordings you find. I played it on several combinations of CDP, amp. and speakers and on a high powered system that fills an auditorium but it's still just a shadow of a great concert even from a well regarded production company
when I spoke of "absolute truth" I did not express myself well.
Personally, it's been a long time since I stopped looking for "the true sound" with zero distortion from the mouth of the Miles's trumpet to my ear.
in "absolute truth" I was referring to the fanatics of naim.
for several years, I'm happy to keep the devices and all I like to listen to and that give me pleasure and they are often different and I always have good surprises as recently with a scott 235s that I have repaired and then restores and I finally kept because this amp is zen
Personally, it's been a long time since I stopped looking for "the true sound" with zero distortion from the mouth of the Miles's trumpet to my ear.
in "absolute truth" I was referring to the fanatics of naim.
for several years, I'm happy to keep the devices and all I like to listen to and that give me pleasure and they are often different and I always have good surprises as recently with a scott 235s that I have repaired and then restores and I finally kept because this amp is zen
PCB Connectors
Hi
Wondering if anyone can point me in the right direction to get hold of some of the PCB connectors I've seen around the place (highlighted on attached photo).
I've had a good dig on ebay and google but the best I can find are either 2-pin or don't have a single through-hole attachment.
I figure this will reduce the time involved in desoldering/resoldering 6 wires per board every time I pull the PCB.
Cheers!
Hi
Wondering if anyone can point me in the right direction to get hold of some of the PCB connectors I've seen around the place (highlighted on attached photo).
I've had a good dig on ebay and google but the best I can find are either 2-pin or don't have a single through-hole attachment.
I figure this will reduce the time involved in desoldering/resoldering 6 wires per board every time I pull the PCB.
Cheers!
Attachments
You don't say how many you need but it greatly reduces your options if you only want a few obsolete metal pressings. The original pin may be a discontinued Vero Technologies part, 1,3mm square. Round types in this size are still available at RS. An important feature of the originals is the barbed retention crimps on the shaft where it is pressed into the board - a once only insertion, I would think. Perhaps Naim service agents there are friendly and you may be able to pull some from a scrap PCB but there will probably be damage that way.
Male spade connectors are available in single pin types that would go close to fitting the same hole, but without the special crimp, you'll need to bend the the tang on the copper side to prevent it being pulled out of the board. You then fit the matching width female terminals to the existing wire leads. see examples C below.
They come under a few titles and it's worth searching Blade connectors and Fast-ons as well.
Male spade connectors are available in single pin types that would go close to fitting the same hole, but without the special crimp, you'll need to bend the the tang on the copper side to prevent it being pulled out of the board. You then fit the matching width female terminals to the existing wire leads. see examples C below.
They come under a few titles and it's worth searching Blade connectors and Fast-ons as well.
Attachments
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My experience with the NAIM 160 clone is very similar.
I think there are three key features to the NAP circuit, at least the circuit I used
a) the toplogy and feedback factor combine to produce a certain harmonic profile
b) the use of a high Cob transistor for the Vas introduces a significant amount of 'imperfect' junction capacitance that swamps any argument about dielectric type for the external Cdom cap. The Vas transistor is quite unusual in this regard, likely 'discovered' through listening waaaay back in the days.
c) the use of tantalum caps at two key points that are outside of the feedback loop, i.e. the distortion they create can not be corrected. This being the input cap and the feedback shunt cap.
This thread makes for interesting reading. I used Naim gear with Quad ESL 57s for about a decade. The 90/92 combination, and then I upgraded the amp to the Naim 140. The Naim gear sounded great compared to other transistor gear I auditioned in the 90s (B&K, I remember). Both Naim amps needed to be recapped after ~5 years connected to the Quads. I finally had a pair of Heathkit UA-2s overhauled. Although they suffered against the Naim 140 in bass control, they were otherwise greatly superior in resolution and overall realism. The Heathkits have been very reliable and tubes go for years in the amps.
Thanks Ian. Again, you're spot on with your information - Fast-on was exactly what I was looking for.
For reference, I've attached the order list from E14. I got some solid housings as well as some of the PVC ones.
Attachments
A challenging point that seems to have escaped the comments of experts, or they've just chosen to remain silent about. Along with an unbalanced LTP, it demystifies much of what goes on in the front end. Replacing the VAS transistors with something modern and fast quickly winds back the "Naim sound" to quite ordinary. If we prefer it that way, there's little point in using the kits for much else.
NAP140 clones usually specify 2SD667/B647 there, which are now common Chinese copies and TO92L versions of 2SD669/B649, in the 12-15pF Cob range like BD139/140. In recent times, alleged clone kits of other NAP amplifiers have appeared, some with original Ferranti/Diodes Inc. ZTX653/753 for the VAS but others with small-signal BC546/556 types which shows us how little some kit producers know about their product and what is required to ensure it works reliably and performs as expected.
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It's not so much the Chinese "clones" that annoy me, because they are typically dirt cheap, but it is stuff like the Avondale Audio NCC200 at £350 per pair. This is atrocious. They do not understand the circuit either although they claim to have greatly improved it.
Helping these sort of people by explaining the circuit in this public forum is not something I want to do. Suffice it to reiterate that the component choices in the Naim amps are neither arbitrary nor incompetent.
Helping these sort of people by explaining the circuit in this public forum is not something I want to do. Suffice it to reiterate that the component choices in the Naim amps are neither arbitrary nor incompetent.
I've got zerozone nap140 clone boards. I tried everyting but cannot succeed about bias.
drivers are mje15030&31.. Vas stage uses ztx653&753. Outputs are 2sc2922.
Feeding the boards with +/-33v.
Bias pot is 2k. I'm measuring bias across the resistor. But pot does no effect at all. I removed outputs last night and checked drivers base to base voltage.. Its zero..
I checked every component.Couldnt find anything yet. Transistor next to bias pot is bc550- i couldnt find ztx384..
What am I missing. Any idea?
Thanks..
drivers are mje15030&31.. Vas stage uses ztx653&753. Outputs are 2sc2922.
Feeding the boards with +/-33v.
Bias pot is 2k. I'm measuring bias across the resistor. But pot does no effect at all. I removed outputs last night and checked drivers base to base voltage.. Its zero..
I checked every component.Couldnt find anything yet. Transistor next to bias pot is bc550- i couldnt find ztx384..
What am I missing. Any idea?
Thanks..
Sorry I thougt you are asking about bias resistors..
Across the pot voltage is around -13v
That's not right. The bias pot voltage should not get much above 3V. IOW the voltage between the bases of the output drivers should not be much above 2.4V when adjusted properly. Check the parts around the pot for value and good connection and that the transistors and diodes are the right way around.
I used 1n4148 diodes. All of them checks ok and direction is alright.
Is it ok to use bc550 in that position?
Not exactly. The pin-out of the BC550 is different to the ZTX. The terminals are the opposite when looking at the flat side of the transistor. So you would need to put the BC in the other way around.
Looking at flat side of ZTX the pins are E-B-C.
Looking at the flat side of BC550 the pins are C-B-E.
I reversed bc550. Now across the pot reading around 1v and its changing with turning pot. still no voltage across base to base of the drivers... Pot is 2k multi turn..That might be my problem. I'll check when I get home..
Thanks